Blank heating system for carton forming machine

ABSTRACT

In a machine for forming tubular cartons from generally rectangular blanks, the blank is heated by two side margin heaters and a transverse heater employing heated gas. The heated gas is supplied to the side margin heaters in countercurrent directions. The transverse heater can be divided at the midpoint and supplied with heated gas at both ends. A perforated conduit supplied with cool gas can be positioned between the blank magazine and the heaters to provide an air curtain between the heaters and the blanks in the magazine.

Ilnited States Patent [1 1 Farfaglia et al.

[ Nov. 12, 1974 BLANK HEATING SYSTEM FOR CARTON FORMING MACHINE [75]Inventors: Silvio T. Farfaglia; Ronald E. Bock,

both of Fulton, NY.

[73] Assignee: Phillips Petroleum Company,

Bartlesville, Okla.

22 Filed: Sept. 7, 1973 211 Appl. No.: 395,035

[52] US. Cl 432/230, 34/105, 93/DIG. 1, 156/497, 156/498 [51] Int. Cl.F27b 17/00 [58] Field of Search 432/230, 231, 146, 77; 34/105; 93/44.].R, DIG. 1; 156/497, 498

[56] References Cited UNITED STATES PATENTS 7/1928 Ritter 432/230 Socke432/230 Kereluk 432/230 Primary Examiner 10hn .I. Camby [57] ABSTRACT Ina machine for forming tubular cartons from generally rectangular blanks,the blank is heated by two side margin heaters and a transverse heateremploying heated gas. The heated gas is supplied to the side marginheaters in countercurrent directions. The transverse heater can bedivided at the midpoint and supplied with heated gas at both ends. Aperforated conduit supplied with cool gas can be positioned between theblank magazine and the heaters to provide an air 7 curtain between theheaters and the blanks in the magazine.

10 Claims, 5 Drawing Figures- PAIENTEUuuv 12 I974 sum 2 OF 4 3.847.540

BLANK HEATING SYSTEM FOR CARTON FORMING MACHINE The invention relates tomeans for heating blanks in a carton forming machine.

In machines for forming tubular cartons from generally rectangularsidewall blanks wherein the blanks are individually withdrawn from amagazine and conveyed through a heating station to a forming mandrel,the heated blank is then wrapped around the mandrel and the overlyingside margins are bonded together to form a tube, and a bottom blank isthen bonded to the bottom end of the tube, there are problems withachieving a uniform heating of the surfaces to be bonded. It is alsodesirable that only the portions to be bonded are heated to anysignificant extent.

Accordingly, it is an object of the present inventio to provide a newand improved means for heating the sidewall blanks. Another object ofthe invention is to minimize the heating of the portions of the blankwhich are not bonding surfaces. Yet another object of the invention isto provide more nearly uniform heating of the surfaces to be bonded.Other objects, aspects and advantages of the invention will be apparentfrom a study of the specification, the drawings and the appended claimsto the invention.

In the drawings,

FIG. 1 is a front elevational view of a carton forming, filling andsealing machine embodying the present invention;

FIG. 2 is a diagrammatic view in elevation of the sidewall blank feedingand heating section and the forming turret of the machine of FIG. 1;

FIG. 3 is a simplified top plan view of the sidewall blank feeding andheating section of FIG. 2;

FIG. 4 is an elevational view, partly in cross section, of thetransverse heater of FIG. 3; and

FIG. 5 is a simplified perspective view showing the relationship of thethree heaters to the sidewall blank being heated.

Referring now to the drawings in detail and to FIG. 1 in particular, thecarton forming, filling and sealing machine comprises a forming section11 and a filling and sealing section 12. The forming section 11comprises a sidewall blank feeding and heating subsection 13, a bottomblank feeding and heating subsection 14, a forming. subsection 15, and atransfer subsection 16. The filling and sealing section 12 has twoparallelendless conveyor systems 17, and each conveyor system comprisesa filling subsection 18 occupying five conveyor stations, a defoamingstation 19, a score breaking station 20, a top heating station 21, afolding and seal-,

ing station 22, a secondary sealing station 23', a branding station 24,and a transfer station 25.

The sidewall blanks 31 manually placed in the sidewall blank magazine 32are flat, relatively stiff single sheets of paperboard, rectangular inshape, scored to provide five longitudinal panels and a gable-topstructure, and coated on both the top and bottom surfaces of each sheetwitha thermoplastic material, e.g., polyethylene. The sidewall blanksare successively withdrawn from magazine 32 and advanced through thesidewall blank heating station 33 to the sidewall blank receivingstation 34 for turret 35. At the sidewall blank heating station 33, theside margins to be'overlapped and the bottom margin of the sidewallblank are heated to a bonding temperature for the thermoplastic coating.

The turret 35 is journalled on a horizontal axis and carries eightcircumferentially spaced apart mandrels 36 extending radially from theaxis of turret 35. The cross section of each of mandrels 36 in a planeperpendicular to its longitudinal axis is generally rectangular.Suitable drive mechanism is provided for indexing or effectingintermittent rotation of the turret 35 to move each mandrel from thesidewall blank receiving station 34 through a blank folding station 37;a bottom end closure forming, applying and sealing station 38; asecondary bottom sealing station 39; a stripping station 40; and threesuccessive nonoperating stations 41, 42 and 43.

The tubular carton body having a bottom closure sealed thereto isremoved from the mandrel 36 at the stripping station 40 and istransferred to a conveyor pocket 45 of one of the two conveyor systems17. The product to be packaged is introduced into the opentopped tubularcarton in the filling subsection 18. If desired, any foam resulting fromthe filling operation can be removed at defoaming station 19. The scoresfor the gable-top structure can be initially folded in the scorebreaking station 20, resulting in the conventional sixsided topstructure. The gable-top ridge panels of the carton are heated instation 21 to a temperature at least as high as the thermal bondingtemperature of the thermoplastic coatings on the carton. The heatedsuperstructure is then folded into contact under pressure at the foldingand sealing station 22 to effect the bonding of adjacent ridge panels.Secondary sealing station 23 applies pressure to the ridge panels duringcooling of the thermoplastic bond. If desired, a data indicia, plantidentification orother information can be applied to the bonded ridgepanels of the sealed carton at branding station 24. The formed, filledand sealed carton is removed from its conveyor pocket 45 at the transferstation 25 and placed on a delivery conveyor 46.

Referring now to FIG. 2, the turret 35 is intermittently rotated in aclockwise direction, as shown on the drawing, by suitable means, notshown. Chain 51 is driven by turret 35 and in turn drives shaft 52.Shaft 52 intermittently drives sidewall conveyor chains 53.

Conveyor chains 53 have dogs 54 to engagea sidewall blank 31 after ithas been withdrawn from the stack to-move the sidewall blank to theheater station 33 and then to the position where the blank can beengaged by the fingers 55 and moved onto the mandrel 36 in'the blankreceiving station. The heater station 33 has electrically heated hot airheater 56 which heats the upper surface of one side edge of sidewallblank 31, heater 57 which heats the lower surface of the opposite sideedge of sidewall blank 31, and transverse heater 58 which heats theupper surface of the trailing end of sidewall blank 31. An air curtainis produced by down-.

wardly directed jets of unheated air from air supply tube 59 when theoperation of the machine is interrupted, thereby providing cooling forthe sidewall blanks in the stack as a protection against damage of thesidewall blanks in the stack by excessive exposure to the hot air fromheaters 56, 57, and 58..

A supply magazine cage 32 for the storage of sidewall blanks 31 isformed by opposing side elements 61 and opposing side elements 61 and 62and opposing end elements 63 and 64 to engage marginal portions of thebottom surface of the lowermost sidewall blanks 31 to support the stackof a plurality of sidewall blanks in cage 32. The magazine cage 32 issupported above the upper run of conveyor chains 53. The blank transfermeans for successively withdrawing individual blanks 31 from themagazine cage 32 and depositing the withdrawn blanks on the upper run ofconveyor chains 53 comprises vacuum cups 67 and the associated mechanism. Vacuum cups 67 are mounted between conveyor chains 53. Cups 67 arereciprocated vertically through openings 68 in plate 69 to engage thebottom surface of central portions of the lowermost sidewall blank andto remove the lowermost sidewall blank 31 from the stack of sidewallblanks in cage 32 by causing the lowermost sidewall blank to moveinwardly and slip past ledges 66. Vacuum cups 67 are connected to asuitable vacuum source 71. In their lower position, cups 67 are belowthe upper surface of plate 69 and the upper edges of conveyor chains 53so as not to interfere with the lateral movement of a blank by conveyorchains 53.

Each vacuum cup 67 is supported by a sleeve 72 attached to a connectingbar 73 by an arm 74. The connecting bar 73 is attached to the upper endof shaft 75. Shaft 75 is reciprocated vertically by linkage 76 and drivecam 77 during the dwell portion of each index cycle for conveyor 54.

Referring now to FIGS. 25, the edge heater 56 comprises an electricalheater 78 having an air passage therethrough, conduit means 79connecting the air inlet of heater 78 to a source of air under pressure,not shown, and a U shaped tube having an upper leg 80 and -a lower leg81. One end of leg 80 is connected to the hot air outlet of heater78'and the remote end of leg 81 is closed. Leg 811 is provided with aseries of orifices 82 spaced along the length of the lower surfacethereof in a pattern which overlies the top surface of the left side (asviewed from magazine 32) margin of blank 31 in heating station 33 todirect jets of heated air against the top surface of said left margin toheat the thermoplastic coating thereon to a suitable bondingtemperature. The lower surface of leg 81 is parallel to the left sideedge of blank 31 and spaced therefrom, and preferably directly overliesthe margin to be heated so that the hot air jets strike the blank 31 atangles of approximately 90, although the angle of impingement of thejets on the blank can vary from 90. The length of the pattern oforifices 82 is preferably coextensive with the length of the side edgeof blank 31.

The edge heater 57 comprises an electrical heater 83 having an airpassage therethrough, conduit means 84 connected to a suitable source ofair underpressure, and an L shaped conduit comprising leg 85 and 86. Oneend of conduit 85 is connected to the heated air outlet of heater 83 andthe remote end of leg 86 is closed. Leg 86 is provided with a series oforifices 87 in the upper surface thereof in a pattern which is at leastsubstantially coextensive'with the length of the right side edge ofblank 31 and which preferably is directly below the right side margin ofblank 31 in the heating station 33, so that the jets of heated airstrike the lower surface of the right side margin to heat thethermoplastic coating thereon to a suitable bonding temperature. Theupper surface of leg 86 is at least substantially parallel to and spacedfrom the right side edge of blank 31. As shown in FIG. 5 the inlet tothe leg 81 is at the top edge of the blank 31 while the inlet to leg 86is at the bottom edge of blank 31. Thus the initial orifice ofleg 81 isadjacent the top margin of blank 31 while the initial orifice of leg 86is adjacent the bottom margin of blank 31. This opposite positioning ofthe two side heaters compensates for any drop in the temperature of theheated air occurring along the length of legs 81 and 86 and provides asubstantially uniform temperature in the bonding area when the heatedmargins are joined.

In the presently preferred embodiment illustrated in the drawings, thetransverse heater 58 comprises first and second electrical heaters 88and 89 having the hot air outlets thereof connected to conduits 90 and91, respectively. The remote ends of conduits 90 and 91 are joinedtogether by partition plate 92 to provide two separate plenum chambers.The air inlets of heaters 88 and 89 are connected to suitable sources ofair under pressure by conduits 93 and 94, respectively. Conduits 90 and91 are provided with a series of orifices 95 in the lower surfacethereof in a pattern which is at least substantially coextensive withthe width of the bottom edge of blank 31, and which preferably directlyoverlies the top surface of the bottom margin of the blank in theheating station 33. The utilization of two heaters 88 and 89 and thepartition 92 at approximately the midpoint of the width of the blank 31minimizes the variation in the temperature to which the various portionsof the bottom margin are heated. The conduits 90 and 91 are positionedwith the lower surface thereof at least substantially parallel to andspaced from the bottom edge of blank 31 inthe heating station 33.

A valve means 96 is positioned between conduit 97 and air tube 59.Conduit 97 is connected to a suitable means of at least substantiallyunheated air under pressure. Conduit 59 is provided with a series oforifices in the lower surface thereof to direct jets of cool airdownwardly to form an air curtain between magazine 32 and transverseheater 58. Valve 96, which is normally closed, is actuated to the openposition by suitable control means whenever the machine is energized butconveyor 53 is deactuated. This air curtain protects the blanks 31 inthe magazine 32 against excessive temperatures, while avoiding theoperational difficulties which would be incurred if heaters 56, S7 and58 had to be deactuated whenever conveyor 53 became deactuated. Withthis system the heaters 56, 57 and 58 continue normal operation and onlythe blank 31 in the heating station 33 is damaged. The damaged blank canbe readily removed by the operator before restarting conveyor 53.

While the invention has been illustrated with rectangular blanks forgable-top cartons, the invention can be utilized with blanks of othergenerally rectangular configuration, for example the approximatelytrapezoidal blanks for frustoconical cartons. In this latter case,heaters 56 and 57 would remain parallel to the edges to be heated butwould not be parallel to each other, and conduits 90 and 91 could havearcuate configuration conforming to the shape of the bottom edge of theblank.

Reasonable variations and modifications are possible within the scope ofthe foregoing disclosure, the drawings, and the appended claims to theinvention.

Thatwhich is claimed is:

1. In a machine for forming a tubular carton from a generallyrectangular flat sidewall blank having thermoplastic coating on theupper and lower surfaces thereof and having first and second sidemargins and top and bottom margins, wherein the sidewall blanks areindividually removed from a sidewall blank magazine and conveyed througha heating station to a forming mandrel, the heated sidewall blank iswrapped around the forming mandrel and the overlapping first and secondside margins are bonded together, the improvement comprising a firstconduit means positioned in said heating station at least generallyparallel to and spaced upwardly from the location which would beoccupied by the upper surface of the first side margin of one of saidblanks in said heating station, said first conduit having orificestherein spaced along the length thereof and directed at the locationwhich would be occupied by said upper surface of said first side marginof the blank in said heating station, a second conduit means positionedin said heating station at least generally parallel to and spaceddownwardly from the loca-.

tion which would be occupied by the lower surface of the second sidemargin of the blank in said heating station, said second conduit meanshaving orifices therein spaced along the length thereof and directed atthe location which would be occupied by the lower surface of said secondside margin of the blank in said heating station, and means forsupplying a hot gas to said first and second conduit means.

2. Apparatus in accordance with claim 1 further comprising third conduitmeans positioned in said heating station at least generally parallel toand spaced from the location which would be occupied by the uppersurface of the bottom margin of the blank in said heating station, saidthird conduit means having orifices therein spaced along the lengththereof and. directed at the location which would be occupied by theupper surface of said bottom margin of the blank in said heatingstation, and means for supplying hot gas to said third conduit means.

3. Apparatus in accordance with claim 2 wherein the means for conveyingthe individual blanks through said heating station is periodicallyactuated to index a blank into position with respect to said first,second and third conduit means.

4. Apparatus in accordance with claim 3 wherein the initial orifice inone of said first and second conduit means isadjacent the location whichwould be occupied by the top margin of the blank in said heating stationand the initial orifice of the other of said first and second conduitsis adjacent the location which would be occupied by the bottom margin ofthe blank in said heating station.

5. Apparatus in accordance with claim 4 wherein said third conduit meanshas a partition therein at about the midpoint of the width of the spacewhich would be occupied by the blank in the heating station to formseparate plenum chambers, and wherein said means for sup plying hot gasto said third conduit means comprises means for supplying hot gas toeach of said plenum chambers at locations remote from said partition.

6. Apparatus in accordance with claim 5 further comprising a fourthconduit means positioned between said magazine and said heating station,said fourth conduit means having a series of orifices therein spacedalong the length thereof to form an air curtain between said magazineand said heating station, and means for providing cool gas to saidfourth conduit means.

7. Apparatus in accordance with claim 6 wherein said means for providingcool gas to said fourth conduit means is actuated only when the machineis actuated but said means for conveying is deactuated.

8. Apparatus in accordance with claim 1 wherein the I initial orifice inone of said first and second conduit means is adjacent the locationwhich would be occupied by the top margin of the blank in said heatingstation and the initial orifice of the other of said first and secondconduits is adjacent the location which would be occupied by the bottommargin of the blank in said heating station.

9. Apparatus in accordance with claim 2 wherein said third conduit meanshas a partition therein at about the midpoint of the width of the spacewhich would be occupied by the blank in the heating station to formseparate plenum chambers, and wherein said means for supplying hot gasto said third conduit means comprises means for supplying hot gas toeach of said plenum chambers at locations remote from said partition.

10. Apparatus in accordance with claim 1 further comprising a fourthconduit means positioned between said magazine and said heating station,said fourth conduit means having a series of orifices therein spacedalong the length thereof to form an air curtain between said magazineand said heating station, and means for providing cool gas to saidfourth conduit means.

1. In a machine for forming a tubular carton from a generallyrectangular flat sidewall blank having thermoplastic coating on theupper and lower surfaces thereof and having first and second sidemargins and top and bottom margins, wherein the sidewall blanks areindividually removed from a sidewall blank magazine and conveyed througha heating station to a forming mandrel, the heated sidewall blank iswrapped around the forming mandrel and the overlapping first and secondside margins are bonded together, the improvement comprising a firstconduit means positioned in said heating station at least generallyparallel to and spaced upwardly from the location which would beoccupied by the upper surface of the first side margin of one of saidblanks in said heating station, said first conduit having orificestherein spaced along the length thereof and directed at the locationwhich would be occupied by said upper surface of said first side marginof the blank in said heating station, a second conduit means positionedin said heating station at least generally parallel to and spaceddownwardly from the location which would be occupied by the lowersurface of the second side margin of the blank in said heating station,said second conduit means having orifices theRein spaced along thelength thereof and directed at the location which would be occupied bythe lower surface of said second side margin of the blank in saidheating station, and means for supplying a hot gas to said first andsecond conduit means.
 2. Apparatus in accordance with claim 1 furthercomprising third conduit means positioned in said heating station atleast generally parallel to and spaced from the location which would beoccupied by the upper surface of the bottom margin of the blank in saidheating station, said third conduit means having orifices therein spacedalong the length thereof and directed at the location which would beoccupied by the upper surface of said bottom margin of the blank in saidheating station, and means for supplying hot gas to said third conduitmeans.
 3. Apparatus in accordance with claim 2 wherein the means forconveying the individual blanks through said heating station isperiodically actuated to index a blank into position with respect tosaid first, second and third conduit means.
 4. Apparatus in accordancewith claim 3 wherein the initial orifice in one of said first and secondconduit means is adjacent the location which would be occupied by thetop margin of the blank in said heating station and the initial orificeof the other of said first and second conduits is adjacent the locationwhich would be occupied by the bottom margin of the blank in saidheating station.
 5. Apparatus in accordance with claim 4 wherein saidthird conduit means has a partition therein at about the midpoint of thewidth of the space which would be occupied by the blank in the heatingstation to form separate plenum chambers, and wherein said means forsupplying hot gas to said third conduit means comprises means forsupplying hot gas to each of said plenum chambers at locations remotefrom said partition.
 6. Apparatus in accordance with claim 5 furthercomprising a fourth conduit means positioned between said magazine andsaid heating station, said fourth conduit means having a series oforifices therein spaced along the length thereof to form an air curtainbetween said magazine and said heating station, and means for providingcool gas to said fourth conduit means.
 7. Apparatus in accordance withclaim 6 wherein said means for providing cool gas to said fourth conduitmeans is actuated only when the machine is actuated but said means forconveying is deactuated.
 8. Apparatus in accordance with claim 1 whereinthe initial orifice in one of said first and second conduit means isadjacent the location which would be occupied by the top margin of theblank in said heating station and the initial orifice of the other ofsaid first and second conduits is adjacent the location which would beoccupied by the bottom margin of the blank in said heating station. 9.Apparatus in accordance with claim 2 wherein said third conduit meanshas a partition therein at about the midpoint of the width of the spacewhich would be occupied by the blank in the heating station to formseparate plenum chambers, and wherein said means for supplying hot gasto said third conduit means comprises means for supplying hot gas toeach of said plenum chambers at locations remote from said partition.10. Apparatus in accordance with claim 1 further comprising a fourthconduit means positioned between said magazine and said heating station,said fourth conduit means having a series of orifices therein spacedalong the length thereof to form an air curtain between said magazineand said heating station, and means for providing cool gas to saidfourth conduit means.